John T I've not done any objective testing on it, but to my ears, it doesn't leave any frequency range completely untouched, wherever you set it. The switch seems to bias it one way or the other, but in practical use, it always comes down to flipping the switch back and forth and using trial and error to get the a sound that does what you want. I agree, John. When set to 'Keep High' there is a bias towards the highs beingĀ 'saturated', but all frequencies are affected. The opposite when set to 'Keep Low'. I have not often found a situation for using the 'Keep Low' setting, personally. For vocals I often use the VX-64 EQ section to apply saturation to only the highs.
Sometimes this works better, sometimes the Softube Knob sounds better. Brian Sonar Platinum, Steinberg Wavelab Pro 9, MOTU 24CoreIO w/ low-slew OP-AMP mods and BLA external clock, True P8, Audient ASP008, API 512c, Chandler Germ500, Summit 2ba-221, GAP Pre-73, Peluso 22251, Peluso 2247LE, Mackie HR824, Polk Audio SRS-SDA 2.3tl w/upgraded Soniccraft crossovers and Goertz cables, powered by Pass-X350. All wiring Star-Quad XLR or Monster Cable.